Cook knife



FIG. 1 is a front perspective view of the claimed design;

FIG. 2 is a front view of the embodiment of FIG. 1;

FIG. 3 is a rear view of the embodiment of FIG. 1;

FIG. 4 is a top view of the embodiment of FIG. 1;

FIG. 5 is a bottom view of the embodiment of FIG. 1;

FIG. 6 is an enlarged right side view of the embodiment of FIG. 1; and,

FIG. 7 is an enlarged left side view of the embodiment of FIG. 1. 

CLAIM I claim the ornamental design for a cook knife, as shown and described. 